HARD REAL TIME PYTHON

[Diez B. Roggisch]

Kurt Mueller wrote:

> David,
> 
> 
> Am 07.10.2008 um 01:25 schrieb Blubaugh, David A.:
>> I have done some additional research into the possibility of utilizing
>> Python for hard real time development.  I have seen on various
>> websites
>> where this has been discussed before on the internet.  However, I was
>> wondering as to how successful anyone has truly been in developing a
>> program project either in windows or in Linux that was or extremely
>> close to real time constraints? For example is it possible to
>> develop a
>> python program that can address an interrupt or execute an operation
>> within 70 Hz or less?? Are there any additional considerations that I
>> should investigate first regarding this matter??
> 
> 
> As others mentioned before, python is not the right tool for "HARD
> REAL TIME".
> 
> But: Maybe you can isolate the part of your application that needs
> "HARD REAL TIME".
>    Then implement this part in an approriate Environment (Language,
> OS, HW).
>    Then implement the rest of your application which is not "HARD
> REAL TIME"
>    in python.
> 
> To be more helpful, we should know what you mean by "HARD REAL TIME".
>    Do you mean:
>    - Handle at least 70 interrupt per second                ("SPEED")
>    - If one fails, this is catastrophic for the application ("HARD")
>    - Deliver an response to an interrupt within 5-10[ms]    ("REAL
> TIME")
> 
> see http://en.wikipedia.org/wiki/Real-time

I've done this using RTAI + ctypes. Of course the hard realtime tasks are
written in C - but only the absolutely minimal core.

Works like a charm.

Diez